نتایج جستجو برای: electron transition

تعداد نتایج: 556612  

Journal: :Physical review letters 2000
S E Kubatkin A V Danilov H Olin T Claeson

We study single-electron transport in quench-condensed bismuth films. By lateral confinement, we select a specific cluster of about 10(3) atoms and use tunneling barriers that appear naturally during thin-film formation. A remarkable reversible increase of the sample conductance up to 5 times was found as the temperature was lowered from 11 to 4 K. We attribute this effect to a spontaneous dist...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2006
Michael S Grinolds Vladimir A Lobastov Jonas Weissenrieder Ahmed H Zewail

Reported here is direct imaging (and diffraction) by using 4D ultrafast electron microscopy (UEM) with combined spatial and temporal resolutions. In the first phase of UEM, it was possible to obtain snapshot images by using timed, single-electron packets; each packet is free of space-charge effects. Here, we demonstrate the ability to obtain sequences of snapshots ("movies") with atomic-scale s...

Journal: :Physical review letters 2012
Cheng Ma Hanzheng Guo Scott P Beckman Xiaoli Tan

We report the first direct evidence that the morphotropic phase boundary in ferroelectric materials, along with the associated strong piezoelectricity, can be created, destroyed, or even replaced by another morphotropic phase boundary through phase transitions during electrical poling. The real-time evolution of crystal structure and domain morphology during the poling-induced phase transitions...

Journal: :Physical chemistry chemical physics : PCCP 2014
M Vogrin N Vaupotič M M Wojcik J Mieczkowski K Madrak D Pociecha E Gorecka

Systematic studies on three dimensionally ordered liquid crystalline phases of different cubic and tetragonal symmetries are presented. The structures of the phases are determined by reconstruction of the electron density distribution from the X-ray diffraction patterns. The known models for electron densities in cubic structures were used whereas a new theoretical model for the structure of th...

Journal: :Physical review letters 2006
J C Loudon P A Midgley

There is considerable controversy surrounding the nature of the paramagnetic to ferromagnetic phase transition in La(0.7)Ca(0.3)MnO3. We have used transmission electron microscopy to determine whether the phase transition is first or second order. On warming through the transition point, the ferromagnetic phase retreats from the sample surface as it is replaced by the paramagnetic phase. This c...

Journal: :Physical review letters 2001
A A Shashkin S V Kravchenko V T Dolgopolov T M Klapwijk

The magnetic field B(c), in which the electrons become fully spin polarized, is found to be proportional to the deviation of the electron density from the zero-field metal-insulator transition in a two-dimensional electron system in silicon. The tendency of B(c) to vanish at a finite electron density suggests a ferromagnetic instability in this strongly correlated electron system.

In this study, mononuclear octahedral cobalt(III) Schiff base complex [CoL3], L = (5-bromo-2-hydroxybenzyl-2-furylmethyl)imine, was synthesized from the reaction of Co(NO3)2•6H2O and the Schiff base ligand L in methanol as solvent. It used as a new precursor to prepare spinel type cobalt oxide nanoparticles by a facile solid-state thermal decomposition. Controlling the temperature and time, Co3...

Journal: :Physical chemistry chemical physics : PCCP 2014
Danna Qian Bo Xu Miaofang Chi Ying Shirley Meng

A novel oxygen vacancy assisted transition metal (TM) diffusion mechanism is proposed for the first time to explain the near-surface phase transformation in lithium excess transition metal layered oxides. Oxygen vacancies and TM migration have been observed at nm scale spatial resolution by Scanning Transmission Electron Microscopy and Electron Energy Loss Spectroscopy. Formation of (dilute) ox...

2013
Yangjie Liu L. K. Ang

In Čerenkov radiation and transition radiation, evanescent wave from motion of charged particles transfers into radiation coherently. However, such dissipative motion-induced radiations require particles to move faster than light in medium or to encounter velocity transition to pump energy. Inspired by a method to detect cloak by observing radiation of a fast-moving electron bunch going through...

2005
Katsunori Kubo Takashi Hotta

In order to investigate multipole ordering in f -electron systems from a microscopic viewpoint, we study the so-called Γ8 models on three kinds of lattices, simple cubic (sc), bcc, and fcc, based on a j-j coupling scheme with f -electron hopping integrals through (ffσ) bonding. From the Γ8 model, we derive an effective model for each lattice structure by using the second-order perturbation theo...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید